Scale-up of natural product formation and isolation

2005 ◽  
Vol 49 (8) ◽  
pp. 732-743 ◽  
Author(s):  
Ralf G. Berger ◽  
Thomas Scheper ◽  
Karl Schügerl
1995 ◽  
Vol 43 (2) ◽  
pp. 199-205 ◽  
Author(s):  
A. W. Alfermann ◽  
Maike Petersen

2022 ◽  
Author(s):  
Jonathan Keim ◽  
Andrew Cummins ◽  
Scott Snyder

In contrast to the tremendous power of Pd-based Mizoroki–Heck reactions, methods to achieve such processes with other metals, particularly Ni, are generally lacking. Herein, we delineate specific conditions that can enable cascade variants of these C–C bond forming events to proceed smoothly under Ni catalysis. Critically, these reactions work with equal facility as their Pd-initiated counterparts when conducted intramolecularly, and in many cases are devoid of any Ni–H-mediated alkene isomerization within the starting materials and/or products as has typically been observed with previous Ni-based protocols. When conducted intermolecularly, the developed variant affords unique regioselectivity in product formation, substantively favoring 6-endo additions over the more standard 5-exo counterparts observed under Pd-based conditions. Finally, applications of the developed procedures to two different natural product syntheses are described


Author(s):  
Teresa Romero Cortes ◽  
Jaime A. Cuervo-Parra ◽  
Víctor José Robles-Olvera ◽  
Eduardo Rangel Cortes ◽  
Pablo A. López Pérez

AbstractEthanol was produced using mucilage juice residues from processed cocoa with Pichia kudriavzevii in batch fermentation. Experimental results showed that maximum ethanol concentration was 13.8 g/L, ethanol yield was 0.50 g-ethanol/g glucose with a productivity of 0.25 g/L h. Likewise, a novel phenomenological model based on the mechanism of multiple parallel coupled reactions was used to describe the kinetics of substrate, enzyme, biomass and product formation. Model parameters were optimized by applying the Levenberg-Marquardt approach. Analysis of results was based on statistical metrics (such as confidence interval), sensitivity and by comparing calculated curves with the experimental data (residual plots). The efficacy of the proposed mathematical model was statistically evaluated using the dimensionless coefficient for efficiency. Results indicated that the proposed model can be applied as a way of augmenting bioethanol production from laboratory scale up to semi-pilot scale.


2013 ◽  
Vol 551 ◽  
pp. 16-24 ◽  
Author(s):  
D.S. van Vuuren ◽  
S.J. Oosthuizen ◽  
J.J. Swanepoel

After evaluating many different routes to produce titanium, the CSIR of South Africa selected a process to produce titanium powder continuously via metallothermic reduction of TiCl4 in molten salt. The project risks are being managed using the well-known STAGE/GATE method. The first two stages, viz, Route Selection and Preliminary Assessment have been completed and the next stage entailing campaigns extending over several days of uninterrupted operation, producing titanium at a rate of about 2 kg/h has recently begun. The rationale for selecting the process route is briefly reviewed and key process problems that had to be solved before embarking on scale-up and measures to do so are explained. Specific problems are: • Feed line blockages, • Titanium product formation and adherence to reactor internals, • Agglomerate formation; and • Production of very fine particles. Lastly the planned schedule and current status of the project are discussed.


Antibiotics ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 133 ◽  
Author(s):  
Saibin Zhu ◽  
Yanwen Duan ◽  
Yong Huang

Microbial natural product drug discovery and development has entered a new era, driven by microbial genomics and synthetic biology. Genome sequencing has revealed the vast potential to produce valuable secondary metabolites in bacteria and fungi. However, many of the biosynthetic gene clusters are silent under standard fermentation conditions. By rational screening for mutations in bacterial ribosomal proteins or RNA polymerases, ribosome engineering is a versatile approach to obtain mutants with improved titers for microbial product formation or new natural products through activating silent biosynthetic gene clusters. In this review, we discuss the mechanism of ribosome engineering and its application to natural product discovery and yield improvement in Streptomyces. Our analysis suggests that ribosome engineering is a rapid and cost-effective approach and could be adapted to speed up the discovery and development of natural product drug leads in the post-genomic era.


2019 ◽  
Author(s):  
Ruchira Mukherji ◽  
Somak Chowdhury ◽  
Pierre Stallforth

LuxR-type transcriptional activator proteins frequently flank bacterial biosynthetic gene clusters (BGCs) where they play a crucial role in regulating natural product formation. Only few bacterial BGCs are expressed under standard culturing conditions, thus modulation of flanking LuxRs is a powerful approach to activate silent clusters. Here, we show that exploiting the modular nature LuxR proteins and constructing chimeric LuxRs enables the activation of BGCs.


2006 ◽  
pp. 439-461 ◽  
Author(s):  
Steven M. Martin ◽  
David A. Kau ◽  
Stephen K. Wrigley
Keyword(s):  

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